I encountered a problem today where a vehicle would not flash correctly. Ultimately it was traced back to some aftermarket HIDs that were flickering while trying to flash. I believe this was causing enough power fluctuation to corrupt the data going to the ECU. After the owner unplugged the HID modules the vehicle flashed normally. So if you're in this situation it's something to keep in mind. I suspect if the DRL module were bypassed or if a capacitor were added to the HID unit it would probably take care of the issue.